Model Output Discussion 26/08/2012

[Summer Sun]

And very interesting and at time close to Hot run from ECM tonight

A settled week gives way to a blip of low pressure

But don't worry this is where is become interesting and close to hot

Pressure rebuilds

Then bingo the perfect set-up

30c is more than possible with that set up

[AWD]

And very interesting and at time close to Hot run from ECM tonight

A settled week gives way to a blip of low pressure

But don't worry this is where is become interesting and close to hot

Pressure rebuilds

Then bingo the perfect set-up

30c is more than possible with that set up

That last chart could bring widespread thunderstorms across the country as that LP slowly edges east.

Shame it's way in FI & unlikely to verify!

Edited September 3, 2012 by Active Weather Dude

[A Winter's Tale]

Good evening everyone.

The current outlook projected by the models to me looks like an enjoyable and interesting one to follow its development as it looks like there could be a fair bit of nice September weather with settled conditions and some pleasant late summer/early autumn warmth whilst rain may continue to threat the NW at times but not excessively so.....thankfully!!!

Tonight however we have some rain over Scotland and parts of Ireland that will move further south east over England and Wales but it should become patchy, light and more drizzly in nature as it progresses SE bringing some cloud with it. Behind it in Scotland and Ireland away from the north western areas should have clear skies and sunshine for the morning, spreading into northern England as the weak front moves south east. And by the afternoon, it should be a fairly decent picture with lots of sunshine over northern England and Wales and and a good part of Scotland away from the north and west where cloud is more likely and Ireland should enjoy some good periods of sunshine too. For the southern third however, cloud cover and spells of drizzly rain is expected for the afternoon and that weak front won't be moving quickly enough to clear by the evening. Temperatures should be in the range of 17-22C. Tuesday night also looks dry other than the odd shower in Scotland where skies are expected to be a little cloudier than the rest of the British Isles and the cloud from that weak front may not have cleared the south coast before midnight, elsewhere a good night for clear skies and quite a cool one too with lows of 11-13C.

The north and west of Scotland again looks like being most at risk or most likely to have cloud cover on Wednesday and skies could be cloudy or mostly cloudy for a time in parts of Ireland and NW England and some spells of cloud cover could be possible even across central England but sunny intervals look lkely throughout Wednesday - particulary in NE England and Scotland. Temperatures not too bad at all with typical highs of 17-21C. And there's no surprise that Wednesday night at the moment looks likely to be a dry one with some good periods of clear starry skies down the western side of England and Wales this time. Cloud cover may hang onto the eastern areas and the northern and western parts of Scotland again is a hotspot for increased cloud cover (although even here clouds should break up for spells) and it looks a similar picture in Ireland. However, there are signs of rainfall as a front approches. Lows could be 10-12C.

Frontal rainfall should arrive for the northern and western Scotland on Thursday and the NW highlands and islands could see some heavy rainfall but the eastern and southern parts of the nation looks like staying dry and largely cloudy and this increase in the likelyhood for cloudy skies extends into northern England and Ireland. The vast majority of Wales and the rest of England is set for a really pleasant day with decent temperatures combined with lovely September sunshine. The rainfall in the NW shouldn't be as heavy or as persistent during Thursday night but again the western and northern areas could be in for a damp night - drier in the east of Scotland. An overcast night for much of Ireland too seems likely but it should stay largely dry other than a little bit of precipitation in the northern coasts. There may be clouds in the night sky across Wales and northern England and possibly the south coast but inland and furthern south east and starry night could be in store. Lows of 11-15C.

There may still be some rainfall in Scotland on Friday but it should be much lighter by then and only restricted to far western and northern fringes. For the rest of Scotland, Ireland, Wales and much of England a really overcast day is expected but a mostly dry one too. The far south coast and south east is forecast to escape the cloudy skies and enjoy the sunshine instead. Quite a warm day with maximum values of 18-23C. A cloudy night for most except the very south coast and rain is still projected to be in the north and west of Scotland and this time it could be a bit heavier (particulary in the very north west of the country) and there could be some light precipitation for parts of Ireland and NW England too. Lows of 12-15C.

The weekend looks fairly decent too at the moment with southerly winds and it should become a lot drier in western and north western parts of Scotland. Temperatures should climb and exceed the 20C mark across much of England and extending into eastern Wales and southern Scotland with temperatures in the high teens elsewhere. Rain is expected to move on from the west on Monday and it could be widespread and heavy down the western side of the British Isles and bringing much cooler temperatures with it to the NW of Scotland with the warmth pushed eastwards but this date is still far away so subtle changes between now and then can influence things greatly. A more unsettled and generally cooler outlook is shown during the latter runs of the GFS 12z but the possibility of winds coming from the SW remains. I'd say that settled and quite warm weather should be here for a while with the threat of rainfall in the Scotland but even here it should be restricted to the western parts of the country so not too bad an outlook here. After that then my current guess is that we'll see more activity in low pressure systems moving across all of the British Isles and air streams could fluctuate between warm and cold of origin so there could be a variety of weather types and a seasonal theme should prevail and the possibility of high pressure influencing from the SW remains but perhaps not as dominant as of the present situation.

[Slowpoke]

Apart from certain areas tomorrow, a fantastic start to September seems to be in-store for England, Wales, Southern Scotland and Ireland (excluding the far North) with the Azores ridging in. It's also very nice to see that humidity won't be too high and with the winds being light meaning even if temperatures only manage the high-teens/low twenties, (as they did today) it'll feel rather pleasant, lovely and warm (as it did today ).

Apart from certain areas tomorrow, a fantastic start to September seems to be in-store for England, Wales, Southern Scotland and Ireland (excluding the far North) with the Azores ridging in. It's also very nice to see that humidity won't be too high and with the winds being light meaning even if temperatures only manage the high-teens/low twenties, (as they did today) it'll feel rather pleasant, lovely and warm (as it did today ).

I am - personally - very pleased.

However, I feel sorry for the far North of Scotland and the Shetland Isles, which looks like experiencing gusts of up to 60mph and heavy rain accompanied by temperatures of just 11-13c, it'd likely feel like an early November low pressure system. For the northern parts of NI It shouldn't be as bad, with temperatures holding up in the mid-teens (14C-17C) and it'll be less windy than in N Scotland the Shetland Isles, though windy enough to make it feel much cooler than the forecast temperatures suggest, unfortunately. All this will be going on in the far North whilst the rest of the country basks in the pleasant conditions. It's a shame, it'll feel like the depths of Autumn at times in the areas I mentioned (N Scotland in-particular).

--------------------------------------------------------------------------------------------------------------------------------

(I'd generally advise to add 1C-3C to these projected temperatures, as per). I'm attending my cousin's wedding on this day (Saturday) and the function suite has a huge open balcony that overlooks Blackpool sea (Hilton Blackpool) so we're all very pleased at the current weather projections.

Could be even warmer if the ECM came off:

Lovely output from the EMS too, possibly up to 30C in places.

--------------------------------------------------------------------------------------------------------------------------------

Another nice outlook here, lovely and warm:

--------------------------------------------------------------------------------------------------------------------------------

It'll be interesting to see if those hot FI charts come to fruition, the week ahead looks lovely for the most of us but it seems mid month a an impressive heatwave could be possible (obviously still FI at the moment). September has proved to be really special and interesting these past few years and this one seems to be following suit. Check this out, 32c-33C possible (FI, I know):

POSSIBLE RECORD BREAKING HEAT IN F.I?!

--------------------------------------------------------------------------------------------------------------------------------

Bring it on!

Edited September 3, 2012 by Slowpoke

[Frosty.]

Another very good ecm run tonight with an outlook which would be more akin to july than mid september. The warm to very warm anticyclonic spell has a hiccup tomorrow with more cloud across the southern half of the uk as a front pushes southeast into the high and there could be some patchy drizzle but then the front decays and disappears as the high gets stronger for the second half of this week, there is another hiccup on sunday as the anticyclonic spell undergoes a necessary reboot then the ecm 12z is showing tropical heat and humidity next week with low pressure anchored out west and high pressure persisting to the east/se, if this trend continues, some september records could get smashed next week.

Edited September 3, 2012 by Frosty039

[damianslaw]

Sticking to the reliable timeframe, it remains a very pleasant outlook away from the far north with plenty of sunny spells light winds and warm temperatures - a taste of late summer, pity we have once again had to wait until September for decent 'summer' synoptics.. the number of times this has happened in recent years is quite unprecedented. Alas, its a welcome outlook given the synoptics of the past 3 months. As many have said much depends on the interaction of ex tropical storm systems as they feed there way into the atlantic, with the jet positioned to remain to our north, such features will either track far to our NW bringing in a southwesterly/southerly flow or possibly stagnate in the mid atlantic to produce possibly a very warm southerly injection of tropical continental air - not something we often see in september but we managed it at the end of last september.

Its a wait and see.. I do think next week will gradually see a breakdown to more unsettled conditions from the NW but it might take time for the SE to turn unsettled, indeed based on longer range model runs, the first half of september could easily rival the 10 day spell in May in terms of delivering the best weather of the year for sunshine and dry settled warm weather - meaning a summer bookended by two lovely spells outside of the 'official' summer season. May and September are the new summer months!

[mushymanrob]

the ecm might be teasing us with some very warm uppers in fi... however with no support from the ukmo or gfs its unlikely to happen.

not so sure temps will be too high either in the forthcoming warm spell, even IF the 15c isotherm 'got here', the suns much lower now, daylength is much shorter, whilst a few short weeks ago it would have produced high temps i dont expect anything too high now, mid 20's at best for most (a few favoured areas might get upper 20's locally).

[WhiteFox]

the ecm might be teasing us with some very warm uppers in fi... however with no support from the ukmo or gfs its unlikely to happen.

not so sure temps will be too high either in the forthcoming warm spell, even IF the 15c isotherm 'got here', the suns much lower now, daylength is much shorter, whilst a few short weeks ago it would have produced high temps i dont expect anything too high now, mid 20's at best for most (a few favoured areas might get upper 20's locally).

Wise words indeed. As with winter weather, so with summery weather. This morning's ECM shows the variability that the ongoing hurricane season injects into medium term forecasts:

Of course, this chart is no more likely to happen than the 192 chart from yesterday, but it's always wise to attach the probability of a forecast verifying before getting too excited about records!

[Gibby]

Good morning. Here's a look at the 00zs from this morning's output.

All models show High pressure moving slowly East over the area as we move through the rest of the week. The far north will be influenced by a strong Westerly flow with severe gales for the far North for a time and some rain too. Further south a weak cold front crossing SE today clears later leaving very light winds, high pressure and fine, sunny conditions by day when it will become warm. Nights in the South though will be a little chilly with some early morning mistiness. By Sunday the Euro models in particular begin to show signs of change.

GFS shows a more unsettled beginning to next week as a trough moves slowly NE over the UK with some rain for all in a SW Breze. By midweek High pressure rebuilds near Ireland with fine conditions returning to many though rather cooler than of late. FI then shows High pressure migrating away to the East and Northeast with Low pressure edging North from France eventually absorbed by deep Atlantic Low pressure moving in fromt he West. Deep FI then shows much windier weather with rain at times as Low pressure to the NW pushes troughs across all areas at times.

The GFS Ensembles illustrate the operatonal quite well this morning as the period after the 11th begins a slow decline to 850's nearer to the long term mean and an increase in rainfall events nationally.

The Jet Stream is shown streaming East over Northern Scotland for the next three days or so before it disrupts somewhat as we move deeper into next week.

UKMO at 144hrs shows a trough in association with Low pressure North of Scotland swinging East over Britain bringing a band of rain across the UK late sunday and early Monday followed by clearer fresher conditions as winds turn NW.

ECM too shows a more unsettled conclusion to it's run as the Jet Stream moves back South and Low pressure's position over or near to the UK by midweek with attendant rain and showers becoming widespread and heavy in places. Consequently things will be turning rather cooler by then.

In Summary it looks like the weather is set fair from now until Sunday away from the extreme North. Dry, bright and reasonably warm conditions should be enjoyed for the vast majority of the UK between now and Sunday. Thereafter, things are shown by all models to become more unsettled with rain and wind becoming more prevalent for most areas as we move deeper into next week.

Edited September 4, 2012 by Gibby

[Gavin Hannah]

GFS showing some potential for a cold incursion by next tuesday.

00Z Run

18Z Run

With that intense looking depression looking like it could make it to the just off the west coast of the UK. A Notable difference too in the position of the HP at the end of the run with the 00Z run pushing the HP further south bringing in more of a westerly atlantic influence.

[Scorcher]

not so sure temps will be too high either in the forthcoming warm spell, even IF the 15c isotherm 'got here', the suns much lower now, daylength is much shorter, whilst a few short weeks ago it would have produced high temps i dont expect anything too high now, mid 20's at best for most (a few favoured areas might get upper 20's locally).

You may well be right, although the high uppers are not only in FI. The ECM is showing the 15C isotherm touching the south coast at T+96. I do seem to recall people saying exactly the same thing in late September last year, ie. the sun was too low and therefore it would stop temperatures getting that high.

[Frosty.]

Let's start with the good news, the models show a lovely anticyclonic spell for most of the uk until sunday with lots of sunshine and light winds but chilly nights with a risk of some mist and fog and dewy early mornings. The far north and northwest remains windier and cooler with some rain at times but occasionally brighter and a little warmer. The Gfs and Ecm ensemble mean tells the story for next week and the T+168 hours snapshot shows low pressure to the northwest winning and the anticyclone moving away or being pushed away into mainland europe and taking all the hot and sunny weather with it. The gfs 00z is actually not a bad run, it does turn cooler and rather more unsettled for a time next week but then atlantic high pressure topples in to bring a more settled spell but not the warmth we will have in the second half of this week but the general trend from the 00z is for a gradual descent into a more unsettled and cooler pattern with the polar front jet occasionally to the south of the BI but still with a chance of some anticyclonic weather from time to time.

Edited September 4, 2012 by Frosty039

[East_England_Stormchaser91]

Isn't it just sods law that this setup always happens in bloody September and not mid-July! If set ups like this occurred in the depths of summer, we would be talking potentially high 30's, no two ways about it! Britain <3

[AWD]

As per with the GFS 12z.

Summery, warm sunny weather over most of the country for the rest of the week and through the weekend.

In this run the warmth and settled conditions manage to hang on through Monday too before a breakdown to unsettled conditions spreads in from the west in Tuesday.

Thereafter an unsettled week next week with rain for all.

A breakdown next week looks quite likely now, it's just a question of whether it's Sunday, Monday or Tuesday IMO!

This weekend could be better than any summer weekend though, looks perfect for outdoor activities!

[Frosty.]

The Gfs 12z op run is a pleasant surprise, after the briefest of wobbles on sunday (in the northern half of the uk), it shows high pressure soon rebuilding across all areas with another fine and warm spell which is good news for scotland and n.ireland as the high becomes centred further north than the current high and with winds becoming SE'ly it looks like temps will again become well above average, indeed the south and southeast barely has a gap between the current very warm anticyclonic spell and the new one early next week but some caution is required because today's meto update did not suggest a nationwide warm and settled spell next week!

Edited September 4, 2012 by Frosty039

[Summer Sun]

Quite a chilly North westerly showing in FI tonight,

Although no snow is shown on the chart below the tops of the Cairngorm's and Ben Nevis could see some snow

Edited September 4, 2012 by Summer Sun

[shedhead]

Isn't it just sods law that this setup always happens in bloody September and not mid-July! If set ups like this occurred in the depths of summer, we would be talking potentially high 30's, no two ways about it! Britain <3

Many of the synoptic setup's we saw across the Summer would have resulted in buckets loads of snow in Winter and just as many setup's we saw last Winter would have produced some serious heat in Summer.

Back to the models and things are starting to look decidedly more Autumnal as we move towards mid month, with this chart unlikely to win many supporters amongst those of us looking for some Indian Summer...

[Polar Maritime]

A very cold end to the GFS with a Northerly showing, Something to keep an eye on during future runs...

[Geordiesnow]

One thing noticetable in the output regarding the medium term is we may see signs of the Atlantic kicking into gear, may not last long though as that massive ex hurricane could always throw up a ridge, I think we need to keep an eye on that ex hurricane and see how that will effect the output in the coming days.

In terms of temperature, nothing Autuminal on the cards, upper are generally warm although it is quite variable at times even this week with cooler air into Northern Britain atm but nothing below 0C mind.

[johnholmes]

One thing noticetable in the output regarding the medium term is we may see signs of the Atlantic kicking into gear, may not last long though as that massive ex hurricane could always throw up a ridge, I think we need to keep an eye on that ex hurricane and see how that will effect the output in the coming days.

In terms of temperature, nothing Autuminal on the cards, upper are generally warm although it is quite variable at times even this week with cooler air into Northern Britain atm but nothing below 0C mind.

yes the effect this will have is getting into a range where we can begin to look at how the 2 main models at that distance are dealing with it.

The 12z from GFS shows it eventually creating a new marked upper trough over the UK which would possibly be the start of a change in overall weather pattern. It may of course do the other variant that GFS has also shown, create a large amount of +ve 500mb anomalies east of its centre and stagnate way out west with relatively warm air still advecting into this country.

Interesting to watch it.

The 10 day outlook on ECMWF version of the 500mb charts this morning shows it trying to cope with a 500mb circulation off Florida.

fifth edit to remove off topic section

Edited September 4, 2012 by chionomaniac

[Cheshire Freeze]

.

As for the 12z outputs, it looks as though the weather will remain generally settled up until Sunday but even then the cold front that pushes N-S looks a weak affair. The north Atlantic synoptic set up is being dicatated by the tropical storm/hurricane activity and so the medium-long term remains fraught with instability in the output. I think if I was to plump with one outcome it would be a pulling south of the jet stream again with periods of windier and wetter weather for all as we progress towards mid September. However, as Gavin P has previously mentioned, there remains a possibility of high pressure around the UK being reinforced by said tropical activity with the trough held out to the W/NW.

Ninth edit

Edited September 4, 2012 by chionomaniac

[Gibby]

Good evening. Here'a a look at today's 12zs from GFS. UKMO and ECM.

All models agree that High pressure dominates the weather over the next 4-5 days. It is shown to drift slowly East over the UK before moving off into Europe later in the weekend with a freshening SW wind. Fine and settled conditions look likely for all with sunny days and cool misty nights in the South while the North see more cloud and a little rain in the far NW as well as strong winds. Later in the weekend things begin to turn more cloudy from the West on Sunday.

GFS then shows cooler conditions as we move into next week though with a lot of dry weather about still as weak High pressure moves East over the UK to settle to the NE with increasing SE winds over the SW half of the UK. As we move through FI the weather slowly turns more unsettled and windy with rain at times and windy too later as a cold NW blast moves down across the UK late in FI before cool High pressure settles things down towards the end of the run with the risk of frost and fog at night briefly.

The GFS Ensembles show a steady cool off in the South from the 11th with some rain at times shown. Further North the fall off in uppers is quicker but more undulating thereafter. The cold plunge shown on the operational was as expected a cold outlier.

The Jet Stream continues to blow West to East over Northern Scotland. GFS predictions next week suggest the current arm of the Jet Stream flow weakens as a new arm sets up on more Southerly latitudes late next week.

UKMO shows a NW flow over the UK with low pressure out to the North. A cold front will of recently crossed bringing fresher conditions and somewhat lower temperatures but still with reasonably bright and fairly dry conditions.

ECM shows High pressure rebuilding near Scotland as we move through next week but in a cooler air mass than we currently have meaning cooler if dry weather with the risk of ground frost in the North. In the South an Easterly flow is set up with a weak Low pressure area to the South a few showers could be exported North for a time before High pressure reasserts itself everywhere briefly with dry and bright conditions before the eventual breakdown occurs on Friday week.

In Summary the weather is fairly straightforward for the next 5 days. Thereafter it is anything but with indecision between the models run to run with various evolutions showing everything from wind and rain, fine and warm, to cool and settled. I think it's a case of waiting a few more days after which a common theme should begin to develop between the models one way or another. IMO I think next week could still see quite a bit of dry weather but I think we need to make the best of the high temperatures down here in the South over the next 4-5 days as the levels they reach may not be repeated for quite a while.

[chionomaniac]

Please keep on topic. We are still 3 months away from winter.........

[legritter]

Im going to enjoy what the models are showing for the next week ,possibly 10 days or so ,beyond that could be autumn in all its glory .slightly off topic but tonights sun set here on mendip ,high clouds crimson ,the odd cumulus pinkish , a green haze out over bristol channel [man made ] one loan Contrail heading south ,probably spain or portugal ,this was a vivid yellow colour ,[man made ] i think i will change man made to human made ,dont want to offend ,some good posts tonight and looking at models and data for beyond 10 days i for one would find it hard to predict whats beyond T 240 hrs .cheers legritter

[A Winter's Tale]

Hi everyone.

The weather for coming days doesn't look too bad at all for this time of year with pleasant to warm temperatures and a fairly decent amount of sunshine so I'd say that there isn't really much to complain about in the near future. During the rest of this evening and night there should be plenty of clear skies for many except in the far south/south east where the cloud should just be clearing into the channel and in some western regions - particular the north west of Scotland - there could be some periods of cloud cover. A dry night too other than the odd shower in Argyll or Lochaber, cooler in the north with lows around 12C and a bit milder in the south at 15C. The picture is very similar for Wednesday morning with lots of lovely early sunshine around for many but there could still be some cloud in the very south and in Welsh hills, parts of Northern Ireland and some of the western regions of Scotland could see some short spells when pockets of cloud cover roll in and there could still be a few showers in the western highlands. Into the afternoon and some more widespread and distinguished cloud cover may move eastwards to bring a spell of cloudy skies across Wales and northern England - for elsehwere largely sunny particulary in the south of England and SW, central Scotland with sunny intervals further west and the odd shower further west. Maximum temperatures of 17-21C. The evening should see cloud cover break up so there could be a few pockets across central, northern and eastern England and some inland parts of Ireland and north sea coast/north west of Scotland could be at risk of some cloud cover but there shoud be less clouds in the sky for most and longer periods of unspoilt clear skies. Wednesday night should be dry with some clouds in the sky for many areas and its more likely to the north west of Scotland and Ireland - elsewhere a few clear breaks in the sky. Lows of 11-12C.

Thursday is likely to be very sunny for a good part of Ireland, Wales and England where temperatures here could max at 19-22C. In northern and western Ireland and some northern parts of England could be overcast and Scotland is likely to have an overcast day and a wet one too with the heaviest and most persistent of the rain in the north west. The rain should break up and lose its intensity during Thursday night but there could be some light precipiation around western fringes of Scotland and NW England and cloud cover associated with the front could be situated over Ireland, the western half of Scotland and northern England, elsehwere it could be a good night for completely clear skies. A milder night too with lows of 12-16C.

The situation on Friday looks very similar to Thursday night but with less rainfall however a cloudy day for most of Scotland, Ireland, northern England and northern Wales is expected with unspoilt sunshine in the southern third and eastern parts of Scotland and Ireland could be lucky and see some sunshine. Quite a warm day too with predicted maximum values of 19-24C. Nothing new to talk about for Friday night with cloud around in northern and western regions, some isolated light rain near the islands of Scotland and clear skies for the south and the east of Ireland and Scotland. A largely mild night with typical lows of 14-16C. It could be cooler in the SW though with possible lows of 9C.

Sunshine on Saturday should become much more widespread with lots of it in Wales and England, quite a bit in Ireland too and some in eastern Scotland aswell. But a band of rain situated to the north west of Scotland could bring some light rain to the northern isles and north western coasts of the mainland and cloud cover associated with the front may extend further inland in Scotland and western parts of Ireland. Nonetheless, temperatures look very decent with typical maximum temperatures of 19C in Scotland and Ireland, into the low to mid 20s in England and in the south east it could be even warmer if not hot with temperatures possibly exceeding 25C. The front should only really bring rain to the Northern Isles during Saturday night but cloud cover again should is expected to extend throughout Scotland. Just about the whole of England, Wales and Ireland could have a fantastic night for clear skies. A cooler night too with lows expected to be in the region of 12-13C.

However, the band of rain to the NW is expected to move south to bring some heavy rain to Scotland and Ireland for a time on Sunday and bring some lighter rain to England and Wales as it moves further south but the South east at the moment is predicted to remain dry and warm. But there is change behind this front as a cool north-westerly develops.

Details will change but initially it's expected to be showery over the NW of the British Isles.

But air pressure still remains high despite the air temperature being cool meaning less precipitation and the above chart shows the line of sub -5C upper air near the Shetland Isles.

GFS also shows cold temperatures early on Tuesday in the north.

The latest run from GFS shows warmer air trying to move northwards in a SEly and it shows rain moving north from the south but the cold air hangs on in the north.